This invention relates to a mower having a steerable reel-type cutting unit. This invention also relates to a mower having a steerable grass catcher associated with a steerable reel-type cutting unit in which the grass catcher is supported on a frame separate from the cutting unit so that the weight of the grass catcher is not carried on the cutting unit. More particularly, this invention relates to such a mower in which the grass catcher as well as the cutting unit can be raised and lowered between a cutting position and a transport position.
Mowers equipped with reel-type cutting units are well known for precision mowing on golf courses and the like. For example, a riding greensmower comprises a traction vehicle on which multiple reel-type cutting units are mounted for mowing golf greens or similar surfaces. Each cutting unit typically comprises a rotatable reel that sweeps the grass against a fixed bedknife and front and rear rollers for allowing the cutting unit to roll over the ground. A grass catcher is mounted generally in front of the cutting unit. The grass catcher includes a grass basket having a rearwardly facing mouth into which the cutting unit throws grass clippings during operation of the greensmower.
In some known mowers of this type, the cutting units can steer themselves about high steering points, i.e. steering points located above the cutting unit, during turns of the mower. For example, if the mower turns to the right, the cutting units similarly steer or yaw to the right in response to the turn. However, in so steering or yawing, these known mowers tend to roll the cutting unit about a longitudinal, horizontal axis such that the end of the cutting unit on the inside of the turn becomes more heavily loaded than the end of the cutting unit on the outside of the turn. This can gouge or scuff the turf which is obviously undesirable. This uneven loading or uneven weight distribution on the cutting unit can also occur when the cutting unit rolls to follow the ground contour even when the cutting unit is travelling straight.
In addition, most of the known reel mowers having steerable cutting units also support the grass basket on the cutting unit itself. Thus, as the grass basket fills with clippings, the weight of the grass basket and the clippings is substantially carried or borne by the cutting unit. A grass basket can hold thirty pounds or so of grass clippings. This additional weight is effectively transferred to the cutting unit frame and lowers the height of cut of the reel from the nominal height the reel cuts when the grass basket is not attached or is empty. This change in the height of cut is also undesirable.
At least some mowers manufactured by The Toro Company, the assignee of this invention, do not place the weight of the grass catcher on the cutting unit to thereby avoid the undesirable change in the height of cut described above. In these mowers, the grass catcher is carried on a support frame that attaches to the mower rather than to the cutting unit such that the weight of the grass catcher and its clippings is not substantially carried by the cutting unit. Further, the cutting unit is often towed or propelled by the grass catcher support frame through two pull link arms that extend from the grass catcher support frame to each side of the cutting unit. While the ends of the pull link arms attach to the cutting unit through ball joints to let the cutting unit roll and pitch relative to the ground to follow the ground contour, the pull link arms and their attachment to a non-steerable grass catcher support frame do not allow the cutting unit to steer or yaw during turns of the mower. Thus, these cutting units slightly skid or wobble during turns.
U.S. Pat. No. 5,533,326, which is assigned to The Toro Company, the assignee of this invention, replaces the two pull link arms on known prior Toro mowers with a single pull link arm attached by a ball joint to the front and middle of the cutting unit. This cutting unit now has movement in all three axes and specifically can steer or yaw during turns of the mower. However, the grass catcher in this mower does not similarly turn or yaw in the same way as the associated cutting unit. Thus, the spacing between the mouth of the grass basket and the cutting reel varies across the width of the cutting unit during a turn. The spacing changes during a turn with the side of the cutting reel on the inside of the turn moving further away from the grass basket and the side of the cutting reel on the outside of the turn moving closer to the grass basket.
This spacing change between the cutting unit and the grass basket can lead to certain operational difficulties. These difficulties include the cutting reel engaging and damaging the grass basket as well as the grass clippings not being properly thrown into the grass basket or falling out of the grass basket in the gap between the cutting unit and the grass basket. To avoid these difficulties, the mower shown in the 326 patent has a partial front shield between the cutting reel and the grass catcher and a flexible seal or barrier extending between this front shield and the mouth of the grass basket.
The use of a front shield/flexible seal as shown in the 326 patent is effective for compensating for the potential problems caused by the change in spacing between the grass basket and the cutting unit during turns. However, when cutting wet and/or sticky grass, the front shield and flexible seal present surfaces and edges to which the grass can adhere and build-up. This build-up can be so extreme that the cutting unit becomes plugged with the area between the grass catcher and the cutting unit, i.e. the area on the top of the flexible seal, becoming more or less substantially filled with grass clippings. Also, the clumps of accumulated clippings occasionally fall to the ground, leaving an unsightly mess. This requires that the mower be stopped and cleaned, which is obviously something that is best avoided. Accordingly, there is a need in the art for another way of solving any problems that are caused by the fact that in some mowers the cutting units can steer during turns of the mower while their separately supported grass catchers cannot.
Mowers of this type also have a lift and lower system for lifting and lowering the cutting units and their grass catchers between cutting and transport positions. In fact, this is done frequently when mowing a green since the operator will lift the cutting units and grass catchers at the end of one pass while the mower is swung around off the green to prepare for another pass and will then lower the cutting units and grass catchers back down as the mower approaches the green for the next cutting pass. One difficulty with some known grass catcher designs is that the baskets tip rearwardly as they are lifted with the result that some clippings could fall out of the baskets when they are lifted. If the flexible seal of the 326 patent is removed, the clippings that fall out of the grass basket would then dribble down onto the ground or fall into the cutting unit, both of which are undesirable.
U.S. Pat. No. 3,408,801 to Kroll, which is assigned to the Toro Manufacturing Corporation, the predecessor of the assignee of this invention, The Toro Company, discloses a walk behind greensmower having a single cutting unit and grass catcher. The grass catcher in the 801 patent has brackets on the sides of the grass catcher which receive pins on the frame of the mower. This pin/bracket configuration allows the grass catcher to shift on the frame of the mower when the user lifts the front of the mower by pushing down on the handle of the mower. The shift in the grass catcher is designed to maintain the grass catcher in a level orientation or even to allow the grass catcher to tip forwardly relative to the mower, thereby to better retain the clippings in the grass catcher.
The pin/bracket configuration shown in the 801 patent does not directly and positively keep the grass catcher level or tipped forwardly during lifting of the front of the mower. It relies on the force of gravity acting on the various components and would be affected by the weight distribution of the clippings inside the grass catcher. Thus, there may be some conditions in which the grass catcher would not reliably shift or tip forwardly during lifting of the front of the mower. Also, the pin/bracket connections shown in the 801 patent potentially would provide excessive movement of the grass basket relative to the mower especially when used on a riding mower capable of relatively higher speed operation. Accordingly, there is still a need in the art for a leveling system for a grass catcher which acts positively on the catcher to ensure that the catcher will always be maintained in a desired position as the lift and lower system operates.
One aspect of this invention relates to a mower which comprises a traction frame. A reel-type cutting unit is provided having a cutting unit frame, a rotatable reel and cooperating bedknife carried on the cutting unit frame, and front and rear rollers carried on the cutting unit frame for allowing the cutting unit to rest on and roll over the ground when the cutting unit is disposed in a cutting position in engagement with the ground as the traction frame moves over the ground. The cutting unit has a weight distribution or loading of an instantaneous nominal value when the cutting unit is on level, flat ground. The cutting unit is operatively coupled to the traction frame in a manner that permits the cutting unit to roll about a horizontal longitudinal x axis and to pitch about a horizontal transverse y axis to follow the ground contour and to steer or yaw about a vertical z axis when the traction frame is turning. The cutting unit is operatively coupled to the traction frame such that the cutting unit steers or yaws about a steering point that is located above and in front of the cutting unit such that the cutting unit casters about this steering point during turns of the traction frame. Finally, the cutting unit is operatively coupled to the traction frame in a manner such that the weight distribution or loading on the cutting unit remains substantially at the instantaneous nominal value thereof even as the cutting unit steers or yaws during turns of the vehicle.
Another aspect of this invention relates to a mower in which the grass catcher and cutting unit both steer or yaw during turns of the mower. This aspect is provided in a mower which comprises a traction frame. A reel-type cutting unit is operatively coupled to the traction frame in a manner that permits the cutting unit to steer or yaw during turns of the traction frame. In addition, a grass catcher is operatively coupled to the traction frame. The grass catcher is located adjacent the cutting unit for receiving grass clippings from the cutting unit. The grass catcher is supported independently of the cutting unit such that the weight of the grass catcher and accumulated grass clippings therein is not substantially carried by the cutting unit. The grass catcher is also operatively coupled to the traction frame in a manner that permits the grass catcher to also steer or yaw during turns of the traction frame.
Yet another aspect of this invention relates to a mower having a level lift grass catcher. This aspect is provided in a mower which comprises a traction frame. A reel-type cutting unit is operatively coupled to the traction frame. A grass catcher is operatively coupled to the traction frame, the grass catcher being located adjacent the cutting unit for receiving grass clippings from the cutting unit. The grass catcher is supported independently of the cutting unit such that the weight of the grass catcher and accumulated grass clippings therein is not substantially carried by the cutting unit. A lift frame is attached to the grass catcher for raising and lowering the grass catcher into and out of engagement with the ground. The lift frame is pivotally connected to the traction frame for rotation about a substantially horizontal pivot axis on the traction frame such that the grass catcher is raised and lowered relative to the ground as the lift frame pivots upwardly and downwardly relative to the traction frame about the substantially horizontal pivot axis on the traction frame. The lift frame is further pivotally connected to the grass catcher such that the grass catcher pivots about a substantially horizontal pivot axis on the lift frame to adjust the orientation of the grass catcher relative to the lift frame as the lift frame pivots upwardly and downwardly relative to the traction frame. A tilt rod extends between the traction frame and the grass catcher to positively tilt the grass catcher forwardly as the lift frame rises.
The above described aspects of this invention are just some of the various aspects of this invention which exist. This invention includes other aspects which have not been specifically enumerated in this Summary of the Invention.